JP7395849B2 - Thermosetting resin composition, its resin sheet, and metal base substrate - Google Patents

Description

The present invention relates to a thermosetting resin composition, a resin sheet thereof, and a metal base substrate.

Heat dissipation properties are required for insulating materials that constitute electrical and electronic equipment. Various developments have been made regarding the heat dissipation properties of insulating materials. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes a thermosetting resin composition using a bisphenol A type epoxy resin as a thermosetting resin and using scaly or spherical boron nitride particles as a thermally conductive filler.

Japanese Patent Application Publication No. 2015-193504

However, as a result of studies conducted by the present inventor, it has been found that the thermally conductive resin composition described in Patent Document 1 has room for improvement in terms of thermal stability of thermal conductivity.

Upon further study, the present inventor found that by appropriately selecting a phenoxy resin that has a mesogenic structure in its molecules (mesogen structure-containing phenoxy resin), the resin thermal conductivity and glass transition of the resin itself without a thermally conductive filler can be improved. It has been found that the temperature can be increased.

Based on these findings, further intensive research revealed that by using resin thermal conductivity and glass transition temperature as guidelines, thermosetting resin compositions with resin thermal conductivity and glass transition temperature of at least predetermined values The present inventors have discovered that the thermal stability of thermal conductivity can be improved, and have completed the present invention.

According to the invention,
A thermosetting resin composition containing a thermosetting resin, a phenoxy resin, and a thermally conductive filler, wherein the phenoxy resin contains a compound having a mesogenic structure in the molecule and does not contain the thermally conductive filler. When preparing the thermosetting resin composition as a composition sample and curing the composition sample to produce a cured sample,
The resin thermal conductivity in the thickness direction of the cured sample is 0.27 W/m·K or more and 3.0 W/m·K or less,
A thermosetting resin composition is provided in which the cured sample has a glass transition temperature of 150°C or more and 400°C or less.

Further, according to the present invention,
a carrier base material;
A resin sheet comprising a resin layer made of the thermosetting resin composition and provided on the carrier base material is provided.

Further, according to the present invention,
a metal substrate;
an insulating layer provided on the metal substrate;
a metal layer provided on the insulating layer,
A metal base substrate is provided, in which the insulating layer is composed of a resin layer made of the thermosetting resin composition or a cured product of the thermosetting resin composition.

According to the present invention, a thermosetting resin composition with excellent thermal conductivity and thermal stability, a resin sheet using the same, and a metal base substrate are provided.

FIG. 1 is a cross-sectional view showing the configuration of a metal base substrate according to the present embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that in all the drawings, similar components are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate. Furthermore, the figure is a schematic diagram and does not correspond to the actual dimensional ratio.

The outline of the thermosetting resin composition of this embodiment will be explained.
The thermosetting resin composition of this embodiment contains a thermosetting resin, a phenoxy resin, and a thermally conductive filler. This phenoxy resin contains a compound having a mesogenic structure in its molecule. This thermosetting resin composition is produced by preparing a thermosetting resin composition that does not contain a thermally conductive filler as a composition sample, curing the composition sample, and producing a cured sample. The resin thermal conductivity is 0.27 W/m·K or more and 3.0 W/m·K or less, and the glass transition temperature of the cured sample is 150° C. or more and 400° C. or less.

As a result of the inventor's studies, the following findings were obtained.
It has been found that the stability of the thermal conductivity of a thermosetting resin composition can be appropriately controlled by using the thermal conductivity and glass transition temperature of the resin itself, which does not contain a thermally conductive filler, as guidelines.
When the thermosetting resin composition contains a thermosetting resin and a phenoxy resin, thermal conductivity and glass transition temperature can be controlled by appropriately selecting a mesogenic structure-containing phenoxy resin as the phenoxy resin. be.
By setting the resin thermal conductivity of the resin alone as a guideline to the above lower limit value or more, and the glass transition temperature of the resin alone to the above lower limit value or more, the thermal conductivity changes before and after heat treatment in the thermosetting resin composition. It has been found that the thermal stability of thermal conductivity can be increased.
Although the detailed mechanism is unknown, it is thought that thermosetting resin compositions with excellent heat resistance and thermal conductivity can stably maintain properties such as thermal conductivity even after exposure to high process temperatures.

The thermosetting resin composition of this embodiment can be used as a heat dissipation insulating material for electric/electronic equipment and the like. This heat dissipation insulating material can be used, for example, as a substrate material for mounting electronic components.

As the electric/electronic device, for example, a normal LED lighting device (a lighting device including an LED as an electronic component), a power supply system device (an electronic device including a power module as an electronic component), etc. can be used. LEDs and power modules generate more heat than ordinary electronic components, so they operate in high-temperature environments and require metal-based substrates.

According to the thermosetting resin composition of this embodiment, a heat dissipating insulating material that can be used for a metal base substrate can be provided.

Each component of the thermosetting resin composition of this embodiment will be explained in detail.

(Phenoxy resin)
The thermosetting resin composition includes a phenoxy resin.
The phenoxy resin according to this embodiment contains a compound having a mesogenic structure (mesogen structure-containing phenoxy resin) in the molecule.

Examples of the mesogenic structure-containing phenoxy resin include those containing a structural unit derived from a phenol compound and a structural unit derived from an epoxy compound in the molecule, and at least one of these structural units contains a compound having a mesogenic structure.
Other examples of the mesogenic structure-containing phenoxy resin include those containing a structural unit derived from a mesogenic structure-containing phenol compound in the molecule.

An example of the above mesogenic structure-containing phenoxy resin can be produced by a known method. It can be obtained by reacting with an epoxy compound.
That is, the phenoxy resin can contain a reaction compound of a polyfunctional phenol compound and a polyfunctional epoxy compound. Either or both of these polyfunctional phenol compounds and polyfunctional epoxy compounds have a mesogenic structure.

Other examples of the above mesogenic structure-containing phenoxy resins can be produced by known methods, such as addition polymerization reaction of a mesogenic structure-containing phenol compound having two or more phenol groups in the molecule into epichlorohydrin. It can be obtained by
That is, the phenoxy resin can include an addition polymer of a phenol compound containing a mesogenic structure.

The production of the above phenoxy resin can be carried out without a solvent or in the presence of a reaction solvent, and examples of the reaction solvent used include aprotic organic solvents such as methyl ethyl ketone, dioxane, tetrahydrofuran, acetophenone, N-methylpyrrolidone, dimethyl Sulfoxide, N,N-dimethylacetamide, sulfolane, cyclohexanone, and the like can be suitably used. By performing solvent substitution after the reaction is completed, it is possible to obtain a resin dissolved in a suitable solvent. Moreover, the phenoxy resin obtained by the solvent reaction can be made into a solid resin that does not contain a solvent by performing a solvent removal treatment using an evaporator or the like.

As reaction catalysts that can be used in the production of the above phenoxy resin, conventionally known polymerization catalysts include alkali metal hydroxides, tertiary amine compounds, quaternary ammonium compounds, tertiary phosphine compounds, quaternary phosphonium compounds, and imidazole. Compounds are preferably used.

The weight average molecular weight (Mw) of the above phenoxy resin is usually 500 to 200,000. It is preferably 1,000 to 100,000, more preferably 2,000 to 50,000. Mw is a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve.

In this embodiment, the mesogenic structure has, for example, a structure represented by the following general formula (1) or general formula (2).
-A ¹ -x-A ² -...(1)
-x-A ¹ -x-...(2)
In the above general formulas (1) and (2), A ¹ and A ² each independently represent an aromatic group, a fused aromatic group, an alicyclic group, or an alicyclic heterocyclic group, and x each independently represents a direct bond, or -O-, -C=C-, -C≡C-, -CO-, -CO-O-, -CO-NH-, -CH=N-, - Represents a divalent bonding group selected from the group consisting of CH=N-N=CH-, -N=N- and -N(O)=N-.

Here, A ¹ and A ² are each independently a hydrocarbon group having 6 to 12 carbon atoms having a benzene ring, a hydrocarbon group having 10 to 20 carbon atoms having a naphthalene ring, and a hydrocarbon group having 12 to 20 carbon atoms having a biphenyl structure. 24 hydrocarbon group, a hydrocarbon group having 12 to 36 carbon atoms having three or more benzene rings, a hydrocarbon group having 12 to 36 carbon atoms having a fused aromatic group, an alicyclic heterocycle having 4 to 36 carbon atoms Preferably, it is selected from the group consisting of: A ¹ and A ² may be unsubstituted or may be derivatives having a substituent.

Specific examples of A ¹ and A ² in the mesogen structure include phenylene, biphenylene, naphthylene, anthracenylene, cyclohexyl, pyridyl, pyrimidyl, and thiophenylene. Further, these may be unsubstituted or may be derivatives having substituents such as an aliphatic hydrocarbon group, a halogen group, a cyano group, and a nitro group.

As x corresponding to the bonding group (linking group) in the mesogen structure, for example, a direct bond, -C=C-, -C≡C-, -CO-O-, -CO-NH-, -CH= Divalent substituents selected from the group N-, -CH=N-N=CH-, -N=N- or -N(O)=N- are preferred.
Here, a direct bond means that A ¹ and A ² in a single bond or a mesogenic structure are connected to each other to form a ring structure. For example, the structure represented by the above general formula (1) may include a naphthalene structure.

As the polyfunctional phenol compound, for example, a mesogenic structure-containing compound represented by the following general formula (A) can be used. These may be used alone or in combination of two or more.

In the above general formula (A), R ¹ and R ³ each independently represent a hydroxy group, and R ² and R ⁴ each independently represent a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms. , a phenyl group, and a halogen atom, a and c are each an integer of 1 to 3, and b and d are each an integer of 0 to 2. However, a+b and c+d are each one of 1 to 3. a+c may be 3 or more.

As the polyfunctional epoxy compound, for example, a mesogenic structure-containing compound represented by the following general formula (B) can be used. These may be used alone or in combination of two or more.

In the above general formula (B), R ⁵ and R ⁷ each independently represent a glycidyl ether group, and R ⁶ and R ⁸ each independently represent a hydrogen atom, a chain or cyclic alkyl having 1 to 6 carbon atoms, represents one selected from a phenyl group, a phenyl group, and a halogen atom, e and g are each an integer of 1 to 3, and f and h are each an integer of 0 to 2. However, e+f and g+h are each one of 1 to 3.

Furthermore, R in the above general formula (A) and general formula (B) represents -A ¹ -x-A ² -, -x-A ¹ -x-, or -x-, respectively. be. Note that the two benzene rings in the above general formula (A) may be connected to each other to form a condensed ring.

Specific examples of the above R ² , R ⁴ , R ⁶ and R ⁸ include, for example, a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a chlorine atom, a bromine atom, etc. Among these, hydrogen atoms and methyl groups are particularly preferred.

As the polyfunctional epoxy compound containing the mesogenic structure, for example, an addition polymer of a compound represented by the above general formula (B) may be used. These may be used alone or in combination of two or more.

Among the polyfunctional phenol compounds and polyfunctional epoxy compounds mentioned above, polyfunctional phenol compounds having three or more hydroxy groups in the molecule and polyfunctional epoxy compounds having two or more epoxy groups in the molecule may be used. good.
That is, the phenoxy resin can include a branched reaction compound of a polyfunctional phenol compound having three or more hydroxy groups in the molecule and a polyfunctional epoxy compound having two or more epoxy groups in the molecule. .

The polyfunctional phenol compound having three or more hydroxy groups in its molecule may include, for example, polyphenol or polyphenol derivatives.
The above polyphenol is a compound containing three or more phenolic hydroxy groups in the molecule. Moreover, this polyphenol preferably has the above-mentioned mesogenic structure in its molecule. For example, a biphenyl skeleton, a phenylbenzoate skeleton, an azobenzene skeleton, a stilbene skeleton, etc. can be used as the mesogenic structure.
Note that the polyphenol derivative includes a compound in which a polyphenol compound having three or more phenolic hydroxy groups and a mesogenic structure is changed to another substituent at a substitutable position of the compound.

In this embodiment, the branched reaction compound includes one or more polyfunctional phenol compounds containing at least three or more hydroxy groups in the molecule, and one or more polyfunctional phenol compounds containing one or more polyfunctional phenol compounds having at least three or more hydroxy groups in the molecule. It can be obtained by using the above polyfunctional epoxy resin.

For example, a combination of a trifunctional phenol compound and a bifunctional epoxy compound, or a combination of a trifunctional phenol compound, a bifunctional phenol compound, and a bifunctional epoxy compound may be used.
As the trifunctional phenol compound, for example, resveratrol represented by the following chemical formula can be used.

As the bifunctional phenol compound, for example, one in which the hydroxy groups of R ¹ and R ³ are bonded to the para position of each benzene ring can be used.
Moreover, as the above-mentioned bifunctional epoxy compound, one in which the above-mentioned R ⁵ and R ⁷ glycidyl ether groups are bonded to the para-position of each benzene ring can be used.
In addition, when the bifunctional phenol compound has a naphthalene ring as a condensed ring, the hydroxy groups of R ¹ and R ³ are located at the 1st and 4th positions, the 1st and 5th positions, the 1st and 6th positions, the 2nd and 2nd positions of the naphthalene ring. It is possible to use a compound bonded between the 2nd and 3rd positions, the 2nd and 6th positions, or the 2nd and 7th positions. In addition, when the bifunctional epoxy compound has a naphthalene ring as a condensed ring, the glycidyl ether groups of R ⁵ and R ⁷ are located at the 1st and 4th positions, the 1st and 5th positions, the 1st and 6th positions of the naphthalene ring, A combination of the 2nd and 3rd positions, the 2nd and 6th positions, or the 2nd and 7th positions can be used.

The above branched reaction compound (branched phenoxy resin) can be obtained by a combination of a trifunctional phenol compound and a bifunctional epoxy compound, or a combination of a trifunctional phenol compound, a bifunctional phenol compound, and a bifunctional epoxy compound as described above. .

On the other hand, among the polyfunctional phenol compound and the polyfunctional epoxy compound, a bifunctional phenol compound and a bifunctional epoxy compound may be used. These may be used alone or in combination of two or more.
That is, the phenoxy resin can include a linear reaction compound of a bifunctional phenol compound having two hydroxy groups in the molecule and a bifunctional epoxy compound having two epoxy groups in the molecule.

As the bifunctional phenol compound, one in which the hydroxy groups of R ¹ and R ³ are bonded to the para position of each benzene ring can be used. Moreover, as the above-mentioned bifunctional epoxy compound, one in which the above-mentioned R ⁵ and R ⁷ glycidyl ether groups are bonded to the para-position of each benzene ring can be used.
In addition, when the bifunctional phenol compound has a naphthalene ring as a condensed ring, the hydroxy groups of R ¹ and R ³ are located at the 1st and 4th positions, the 1st and 5th positions, the 1st and 6th positions, the 2nd and 2nd positions of the naphthalene ring. It is possible to use a compound bonded between the 2nd and 3rd positions, the 2nd and 6th positions, or the 2nd and 7th positions. In addition, when the bifunctional epoxy compound has a naphthalene ring as a condensed ring, the glycidyl ether groups of R ⁵ and R ⁷ are located at the 1st and 4th positions, the 1st and 5th positions, the 1st and 6th positions of the naphthalene ring, A combination of the 2nd and 3rd positions, the 2nd and 6th positions, or the 2nd and 7th positions can be used.
By using such a bifunctional phenol compound and a bifunctional epoxy compound together, the above linear reaction compound (linear phenoxy resin) can be obtained.

The above-mentioned branched phenoxy resin and linear phenoxy resin can have an epoxy group or a hydroxy group at the end of the molecule, and an epoxy group or a hydroxy group inside the molecule. By having an epoxy group at the end or inside, a crosslinking reaction can be formed, so heat resistance can be improved.
Further, by having a linear structural unit that is rigid and electronically conjugated, heat dissipation characteristics can be improved.

The content of the phenoxy resin is, for example, 1% by mass to 70% by mass, preferably 2% by mass to 50% by mass, based on the resin component (100% by mass) of the thermosetting resin composition containing no filler. More preferably, it is 3% by mass to 45% by mass.

In this specification, "~" indicates that the upper limit value and the lower limit value are included, unless otherwise specified. Furthermore, in a thermosetting resin composition that does not contain fillers, the term "filler" includes ordinary fillers such as thermally conductive fillers, inorganic fillers, or organic fillers, which will be described later. That is, a thermosetting resin composition that does not contain a filler is composed of a resin component other than the filler, and includes, for example, a thermosetting resin and a phenoxy resin as the resin component.

(thermosetting resin)
The thermosetting resin composition contains a thermosetting resin other than phenoxy resin.
Examples of the thermosetting resin include thermosetting compounds containing a mesogenic structure (mesogen skeleton) in the molecule and thermosetting compounds not containing a mesogenic structure in the molecule.

Examples of the thermosetting resin include epoxy resin, polyimide resin, benzoxazine resin, unsaturated polyester resin, cyanate ester resin, phenol resin, melamine resin, silicone resin, bismaleimide resin, acrylic resin, and phenol derivatives thereof. Examples include derivatives. As these thermosetting resins, monomers, oligomers, and polymers in general having two or more reactive functional groups in one molecule can be used, and the molecular weight and molecular structure thereof are not particularly limited.
These may be used alone or in combination of two or more.

The thermosetting resin may include one or more selected from the group consisting of epoxy resins and phenol derivatives.

The above-mentioned phenol derivative is not particularly limited as long as it is a compound synthesized using a phenol compound, and examples thereof include benzoxazine compounds, novolac resins, and resol resins.
The above-mentioned phenol derivative preferably has a mesogenic structure in its molecule from the viewpoint of high thermal conductivity. The above-mentioned phenol derivative can be synthesized using a phenol compound or an amine compound having a mesogenic structure in the molecule.

The benzoxazine compound may include, for example, a benzoxazine compound containing a mesogenic structure represented by the following general formula (c1) or (c2).

In the above general formulas (c1) and (c2), each R is a bonding group represented by -x- as described above.

In addition, in the above general formulas (c1) and (c2), R' each independently represents a hydrogen atom, a lower alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkynyl group, which are the same or different. represent. Further, the benzene ring in the general formulas (c1) and (c2) may be unsubstituted or may have a substituent such as an aliphatic hydrocarbon group or an aromatic hydrocarbon group. In addition, the benzoxazine compound may have a functional group such as a crosslinkable group or a polar group such as nitrile.

The content of the thermosetting resin is, for example, preferably 0.1% by mass or more and 70% by mass or less, and 0.5% by mass or less, based on the resin component (100% by mass) of the thermosetting resin composition containing no filler. The content is more preferably 1% by mass or more and 65% by mass or less, and even more preferably 1% by mass or more and 60% by mass or less. When it is at least the above lower limit, curability improves and it becomes easy to form a resin layer. When it is below the above upper limit, the storage stability of the resin layer is further improved, and the thermal conductivity of the resin layer is further improved.

(hardening agent)
The thermosetting resin composition may contain a curing agent, if necessary.
The curing agent is selected depending on the type of thermosetting resin, and is not particularly limited as long as it reacts with the thermosetting resin.

Examples of the curing agent include phenolic resin curing agents, amine curing agents, acid anhydride curing agents, and mercaptan curing agents. These may be used alone or in combination of two or more.

Examples of the above-mentioned phenolic resin curing agents include phenol novolac resins, cresol novolak resins, naphthol novolak resins, aminotriazine novolak resins, novolak resins, novolak type phenolic resins such as tris-phenylmethane type phenol novolak resins; terpene-modified phenolic resins, Modified phenol resins such as cyclopentadiene-modified phenol resin; phenol aralkyl resins having a phenylene skeleton and/or biphenylene skeleton; aralkyl type resins such as naphthol aralkyl resins having a phenylene skeleton and/or biphenylene skeleton; bisphenols such as bisphenol A and bisphenol F Compounds include resol type phenolic resins, etc., and these may be used alone or in combination of two or more. Among these, a novolac type phenol resin or a resol type phenol resin can be used from the viewpoint of improving the glass transition temperature and reducing the coefficient of linear expansion.

(hardening accelerator)
The thermosetting resin composition may contain a curing accelerator, if necessary.
The type and amount of the curing accelerator mentioned above are not particularly limited, but an appropriate one can be selected from the viewpoints of reaction rate, reaction temperature, storage stability, etc.

Examples of the curing accelerator include imidazoles, organic phosphorus compounds, tertiary amines, phenol compounds, and organic acids. These may be used alone or in combination of two or more. Among these, from the viewpoint of improving heat resistance, it is preferable to use nitrogen atom-containing compounds such as imidazoles.

Examples of the imidazole include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2,4-diethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole. , 2-phenyl-4,5-dihydroxymethylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and the like.

Examples of the above-mentioned tertiary amines include triethylamine, tributylamine, 1,4-diazabicyclo[2.2.2]octane, and 1,8-diazabicyclo(5,4,0)undecene-7.
Examples of the phenol compound include phenol, bisphenol A, nonylphenol, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, and the like.
Examples of the organic acids include acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid.

The content of the curing accelerator may be 0.01% by mass to 10% by mass, or 0.02% by mass to 5% by mass, based on the total of 100% by mass of the thermosetting resin and curing agent. It may be 0.05% by mass to 1.5% by mass.

(thermal conductive filler)
The thermosetting resin composition includes a thermally conductive filler.
The thermally conductive filler can include, for example, highly thermally conductive inorganic particles having a thermal conductivity of 20 W/m·K or more. The highly thermally conductive inorganic particles may include, for example, at least one selected from alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and magnesium oxide. These may be used alone or in combination of two or more.

In the thermally conductive filler, the boron nitride may include monodispersed particles, aggregated particles, or a mixture thereof of flaky boron nitride. The flaky boron nitride may be granulated. By using aggregated particles of scale-like boron nitride, thermal conductivity can be further enhanced. The aggregated particles may be sintered particles or non-sintered particles.

The content of the thermally conductive filler is 100% by mass to 400% by mass, preferably 150% by mass to 350% by mass, based on the resin component (100% by mass) of the thermosetting resin composition containing no filler. %, more preferably 200% to 300% by mass. Thermal conductivity can be improved by setting it to the above lower limit or more. By setting it below the above-mentioned upper limit, deterioration in processability can be suppressed.

The thermosetting resin composition may include a silane coupling agent.
Thereby, the compatibility of the thermally conductive filler in the thermosetting resin composition can be improved. The coupling agent may be added to the thermosetting resin composition, or may be used by treating the surface of the thermally conductive filler.

Examples of the silane coupling agents include epoxy silane coupling agents, amino silane coupling agents, mercapto silane coupling agents, ureido silane coupling agents, cationic silane coupling agents, and titanate coupling agents. and a silicone oil type coupling agent. These may be used alone or in combination of two or more.
Among these, a silane coupling agent having at least one of an epoxy group, an amino group, a mercapto group, a ureido group, or a hydroxy group as a functional group can be used. Furthermore, from the viewpoint of improving compatibility with the resin component, a silane coupling agent having a non-reactive phenyl group can be used.

Specific examples of the silane coupling agent having the above functional group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, Glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2- Examples include aminoethyl)aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptotriethoxysilane, and 3-ureidopropyltriethoxysilane. Examples of the silane coupling agent containing a phenyl group include 3-phenylaminopropyltrimethoxysilane, 3-phenylaminopropyltriethoxysilane, N-methylanilinopropyltrimethoxysilane, and N-methylanilinopropyltrimethoxysilane. Ethoxysilane, 3-phenyliminopropyltrimethoxysilane, 3-phenyliminopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, triphenylmethoxysilane, triphenylethoxysilane, etc. can be mentioned.

The amount of the coupling agent added is preferably, for example, 0.05% by mass or more and 3% by mass or less, particularly preferably 0.1% by mass or more and 2% by mass or less, based on 100% by mass of the thermally conductive filler.

The thermosetting resin composition of this embodiment can contain other components other than the components mentioned above. Examples of other components include antioxidants and leveling agents.

Examples of methods for producing the thermosetting resin composition of this embodiment include the following methods.
A resin varnish (varnish-like thermosetting resin composition) can be prepared by dissolving, mixing, and stirring each of the above components in a solvent. For this mixing, various mixers such as an ultrasonic dispersion method, a high-pressure collision dispersion method, a high-speed rotation dispersion method, a bead mill method, a high-speed shear dispersion method, and a rotation-revolution dispersion method can be used.

The above solvents are not particularly limited, but include acetone, methyl isobutyl ketone, toluene, ethyl acetate,
Examples include cyclohexane, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve series, carbitol series, anisole, and N-methylpyrrolidone.

The characteristics of the thermosetting resin composition of this embodiment will be explained.
Properties of thermosetting resin compositions include both resin properties and composite properties.

The resin properties are measured using the following composition sample A or cured sample A.
The composition sample A is prepared as a thermosetting resin composition that is composed of a mixture of components other than the filler among the constituent components of the thermosetting resin composition and does not contain filler. The term "filler" used herein includes ordinary fillers such as the above-mentioned thermally conductive fillers, inorganic fillers, and organic fillers.
The cured sample A is obtained by curing composition sample A under predetermined conditions.

Further, the composite properties are measured using the following cured sample B.
The cured sample B is obtained by using a thermosetting resin composition containing a filler such as a thermally conductive filler as the composition sample B, and curing the composition sample B under predetermined conditions.

The above-mentioned cured samples A and B may be processed into test pieces of predetermined dimensions as necessary, may be B-staged under predetermined conditions before curing, or may be subjected to a drying treatment under predetermined conditions after curing. .

The thermosetting resin composition of this embodiment has the following characteristics 1 and 2.
(Characteristic 1) The lower limit of the resin thermal conductivity in the thickness direction of cured sample A is 0.27 W/m・K or more, preferably 0.28 W/m・K or more, more preferably 0.29 W/m・K That's all. The upper limit of the resin thermal conductivity is not particularly limited, but may be, for example, 3.0 W/m·K or less, preferably 2.5 W/m·K or less, more preferably 2.0 W/m·K or less. .
(Characteristic 2) The lower limit of the glass transition temperature of cured sample A is 150°C or higher, preferably 190°C or higher, and more preferably 200°C or higher. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but may be 400°C or lower, preferably 350°C or lower, and more preferably 300°C or lower.

In the thermosetting resin composition of the present embodiment, the thermal conductivity of property 1 is set to be equal to or higher than the above lower limit value, and the glass transition temperature of property 2 is set to be equal to or higher than the above lower limit value, whereby the thermal conductivity changes before and after heat treatment. can be suppressed and the thermal stability of thermal conductivity can be improved.

The storage modulus of the cured sample A at 25° C. is, for example, 1.7 GPa to 5.0 GPa, preferably 1.8 GPa to 4.5 GPa, more preferably 1.9 GPa to 4.0 GPa. By setting it to the lower limit or more, a metal base substrate with excellent mechanical strength can be realized.

The 5% weight loss temperature (Td5) of the cured sample A is, for example, 330°C to 500°C, preferably 340°C to 480°C, more preferably 350°C to 450°C. By setting it to the lower limit or more, a metal base substrate with excellent heat resistance can be realized.

The linear expansion coefficient of the cured sample A in the plane direction (XY direction) in the range of 40°C to 60°C is, for example, 30 ppm/°C to 90 ppm/°C, preferably 35 ppm/°C to 80 ppm/°C, more preferably 40 ppm/°C. /°C to 70 ppm/°C. By setting the value within such a numerical range, it is possible to improve the stress relaxation ability at high temperatures and realize a metal base substrate with excellent reliability.

The composite thermal conductivity in the thickness direction of the cured sample B is, for example, 5 W/m·K to 50 W/m·K, preferably 8 W/m·K to 30 W/m·K. By setting the value within such a numerical range, the heat dissipation characteristics of the composite molded article can be improved.

(resin sheet)
The resin sheet of this embodiment includes a carrier base material and a resin layer made of the thermosetting resin composition of this embodiment provided on the carrier base material.

The resin sheet can be obtained, for example, by subjecting a coating film (resin layer) obtained by coating a varnish-like thermosetting resin composition onto a carrier base material to a solvent removal treatment. The solvent content in the resin sheet can be 10% by weight or less based on the entire thermosetting resin composition. For example, the solvent removal treatment can be performed at 80° C. to 200° C. for 1 minute to 30 minutes.

Further, in this embodiment, as the carrier base material, for example, a polymer film, metal foil, etc. can be used. The polymer film is not particularly limited, but includes, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, release papers such as silicone sheets, and heat-resistant materials such as fluorine resins and polyimide resins. Examples include thermoplastic resin sheets having the following properties. The metal foil is not particularly limited, but includes, for example, copper and/or copper-based alloys, aluminum and/or aluminum-based alloys, iron and/or iron-based alloys, silver and/or silver-based alloys, gold and gold-based alloys. , zinc and zinc-based alloys, nickel and nickel-based alloys, tin and tin-based alloys, and the like.

(resin substrate)
The resin substrate of this embodiment includes an insulating layer made of a cured product of the thermosetting resin composition. This resin substrate can be used as a material for a printed circuit board on which electronic components such as LEDs and power modules are mounted.

(metal base board)
The metal base substrate 100 of this embodiment will be explained based on FIG. 1.
FIG. 1 is a cross-sectional view showing an example of the configuration of a metal base substrate 100.
As shown in FIG. 1, the metal base substrate 100 can include a metal substrate 101, an insulating layer 102 provided on the metal substrate 101, and a metal layer 103 provided on the insulating layer 102. . This insulating layer 102 can be composed of one selected from the group consisting of a resin layer made of the above-mentioned thermosetting resin composition, a cured product of the thermosetting resin composition, and a laminate. Each of these resin layers and laminates may be composed of a thermosetting resin composition in a B-stage state before the circuit processing of the metal layer 103, and after the circuit processing, it is hardened. It may also be a cured product.

The metal layer 103 is provided on the insulating layer 102 and is subjected to circuit processing. Examples of the metal constituting this metal layer 103 include one or more selected from copper, copper alloy, aluminum, aluminum alloy, nickel, iron, tin, and the like. Among these, the metal layer 103 is preferably a copper layer or an aluminum layer, and particularly preferably a copper layer. By using copper or aluminum, the circuit workability of the metal layer 103 can be improved. The metal layer 103 may be made of metal foil that is available in plate form or may be made of metal foil that is available in roll form.

The lower limit of the thickness of the metal layer 103 is, for example, 0.01 mm or more, preferably 0.035 mm or more, so that it can be applied to applications requiring high current.
Further, the upper limit of the thickness of the metal layer 103 is, for example, 10.0 mm or less, preferably 5 mm or less. When the value is below such a value, circuit workability can be improved and the overall thickness of the board can be reduced.

The metal substrate 101 has a role of dissipating heat accumulated in the metal base substrate 100. The metal substrate 101 is not particularly limited as long as it is a heat-dissipating metal substrate, and examples thereof include a copper substrate, a copper alloy substrate, an aluminum substrate, and an aluminum alloy substrate. A copper substrate or an aluminum substrate is preferable, and a copper substrate is more preferable. By using a copper substrate or an aluminum substrate, the metal substrate 101 can have good heat dissipation properties.

The thickness of the metal substrate 101 can be appropriately set as long as the purpose of the present invention is not impaired.
The upper limit of the thickness of the metal substrate 101 is, for example, 20.0 mm or less, preferably 5.0 mm or less. It is possible to improve the workability of the metal base substrate 100 having a value equal to or less than this value in external shape processing, cutting processing, etc.
Further, the lower limit of the thickness of the metal substrate 101 is, for example, 0.01 mm or more, preferably 0.6 mm or more. By using the metal substrate 101 having a value greater than or equal to this value, the heat dissipation performance of the metal base substrate 100 as a whole can be improved.

In this embodiment, the metal base substrate 100 can be used for various substrate applications, and because it has excellent thermal conductivity and heat resistance, it can be used as a printed circuit board for use with LEDs and power modules. .
The metal base substrate 100 can have a metal layer 103 processed into a circuit by etching or the like into a pattern. In this metal base substrate 100, a solder resist (not shown) may be formed on the outermost layer, and connection electrode portions may be exposed so that electronic components can be mounted by exposure and development.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and the present invention includes modifications, improvements, etc. within a range that can achieve the purpose of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the description of these Examples.

(Preparation of thermosetting resin composition containing no thermally conductive filler)
According to the compounding ratio shown in Table 1, thermosetting resin, phenoxy resin, and if necessary, a curing accelerator are melt-mixed on a hot plate, and after cooling, if it is solid, it is pulverized, and if it is liquid, it is crushed. It was used as it was as a thermosetting resin composition.

(Preparation of thermosetting resin varnish containing thermally conductive filler)
According to the blending ratio shown in Table 1, a thermosetting resin, a phenoxy resin, a curing accelerator as necessary, a thermally conductive filler, and a solvent were stirred to obtain a varnish-like thermosetting resin composition.
In Table 1, the content of the thermally conductive filler was 50% by volume with respect to the resin component (100% by mass) of the thermosetting resin composition not containing the thermally conductive filler.

Each component listed in Table 1 is as follows.

(hardening accelerator)
・Curing accelerator 1: Phenol resin (Meiwa Kasei, MEH-7500)

(thermosetting resin)

・Benzoxazine compound 1: Benzoxazine compound represented by the following chemical formula (no mesogen structure, manufactured by Shikoku Kasei Co., Ltd., P-d)

・Benzoxazine compound 2: Benzoxazine compound represented by the following chemical formula (with mesogenic structure, PH-tol)

・Epoxy compound 1: Dicyclopentadiene type epoxy resin represented by the chemical formula below (no mesogen structure, solid epoxy resin, manufactured by DIC Corporation, HP-7200)

(Phenoxy resin)
・Linear chain phenoxy resin A: Bisphenol A type phenoxy resin represented by the chemical formula below (no mesogen structure, manufactured by Mitsubishi Chemical Corporation, YP-55)

・Branched phenoxy resin B: Branched phenoxy resin B obtained by the following synthesis procedure A
(Synthesis procedure A)
8.9 parts by weight of ester group-containing bisphenol (bifunctional phenol compound, with a mesogenic structure, in-house preparation) represented by the chemical formula below, and tetramethylbiphenyl type epoxy resin (bifunctional epoxy compound, mesogen structure) represented by the chemical formula below. Structured, manufactured by Mitsubishi Chemical Corporation, YX4000) 56.5 parts by weight and trifunctional mesogenic phenol represented by the following chemical formula (trifunctional phenol compound, with mesogenic structure, manufactured by Evolva, resveratrol) 6.0 parts by weight 1 part by weight, 0.1 part by weight of triphenylphosphine (TPP), and 28.5 parts by weight of methyl ethyl ketone were charged into a reactor and reacted at 120° C. while removing the solvent. After confirming by GPC that the desired molecular weight was achieved, the reaction was stopped. A branched phenoxy resin B having a weight average molecular weight of 9300 (based on polystyrene refractive index) was obtained.

・Branched phenoxy resin C: Branched phenoxy resin C obtained by the following synthesis procedure B
(Synthesis procedure B)
Synthesis was carried out using synthesis procedure A, except that 2,6-DON modified epoxy (a bifunctional epoxy compound, with a mesogenic structure) represented by the chemical formula below was used in place of the above tetramethylbiphenyl type epoxy resin. A branched phenoxy resin B having an average molecular weight of 9,300 was obtained.

・Branched phenoxy resin D: Branched phenoxy resin D obtained by the following synthesis procedure C
(Synthesis procedure C)
In place of the above ester group-containing bisphenol, 4,4'-dihydroxybiphenyl (a bifunctional phenol compound, with a mesogenic structure, manufactured by Tokyo Kasei Kogyo Co., Ltd.) represented by the chemical formula below was used, and in place of the above tetramethylbiphenyl type epoxy resin. Synthesis was carried out using synthesis procedure A, except that a mixture of biphenyl-type epoxy resin and tetramethylbiphenyl-type epoxy resin (mixture of bifunctional epoxy compounds, with mesogenic structure, manufactured by Mitsubishi Chemical Corporation, YL6121HA) was used. A branched phenoxy resin C having an average molecular weight of 9,200 was obtained.

・Branched phenoxy resin E: Branched phenoxy resin E obtained by the following synthesis procedure D
(Synthesis procedure D)
The ester group-containing bisphenol represented by the above chemical formula, the mixture of the above biphenyl type epoxy resin and the tetramethylbiphenyl type epoxy resin (mixture of bifunctional epoxy compounds, with mesogenic structure, manufactured by Mitsubishi Chemical Corporation, YL6121HA), and the above trifunctional A branched phenoxy resin D having a weight average molecular weight of 8,000 was obtained by performing synthesis using synthesis procedure A except for using a synthetic mesogenic phenol.

・Linear chain phenoxy resin F: Linear phenoxy resin F obtained by the following synthesis procedure E
(Synthesis procedure E)
22.9 parts by weight of ester group-containing bisphenol (bifunctional phenol compound, with mesogenic structure, in-house preparation) represented by the chemical formula below, and tetramethylbiphenyl type epoxy resin (bifunctional epoxy compound, mesogen structure) represented by the chemical formula below. 72.4 parts by weight of YX4000 (manufactured by Mitsubishi Chemical Corporation), 0.1 parts by weight of triphenylphosphine (TPP), and 4.6 parts by weight of methyl ethyl ketone were added to a reactor, and the solvent was removed at 120°C. The reaction was performed while removing. After confirming by GPC that the desired molecular weight was achieved, the reaction was stopped. A linear phenoxy resin F having a weight average molecular weight of 7,800 (based on polystyrene refractive index) was obtained.

・Linear chain phenoxy resin G: Linear phenoxy resin G obtained by the following synthesis procedure F
(Synthesis procedure F)
Synthesis was carried out in the same manner as in Synthesis Procedure F, except that 2,6-DON modified epoxy (bifunctional epoxy compound, with mesogenic structure) represented by the following chemical formula was used instead of the above tetramethylbiphenyl type epoxy resin, A linear phenoxy resin B having a weight average molecular weight of 7,400 was obtained.

・Linear chain phenoxy resin H: Linear phenoxy resin H obtained by the following synthesis procedure G
(Synthesis procedure G)
Synthesis was carried out in the same manner as in Synthesis Procedure F, except that 2,7-DON modified epoxy (bifunctional epoxy compound, with mesogenic structure) represented by the following chemical formula was used instead of the above tetramethylbiphenyl type epoxy resin, A linear phenoxy resin H having a weight average molecular weight of 7900 was obtained.

・Linear chain phenoxy resin I: Linear phenoxy resin I obtained by the following synthesis procedure H
(Synthesis procedure H)
Synthesis was carried out in the same manner as in Synthesis Procedure F, except that a terephthalylidene epoxy resin (DGETAM, a bifunctional epoxy compound, with a mesogenic structure) represented by the chemical formula below was used in place of the above tetramethylbiphenyl epoxy resin. A linear phenoxy resin I having an average molecular weight of 8900 was obtained.

・Linear chain phenoxy resin J: Linear phenoxy resin J obtained by the following synthesis procedure I
(Synthesis procedure I)
In place of the above ester group-containing bisphenol, 4,4'-dihydroxybiphenyl (a bifunctional phenol compound, with a mesogenic structure, manufactured by Tokyo Kasei Kogyo Co., Ltd.) represented by the chemical formula below was used, and in place of the above tetramethylbiphenyl type epoxy resin. Synthesis was carried out in the same manner as in Synthesis Procedure F, except that a mixture of biphenyl-type epoxy resin and tetramethylbiphenyl-type epoxy resin (mixture of bifunctional epoxy compounds, with mesogenic structure, manufactured by Mitsubishi Chemical Corporation, YL6121HA) was used. A linear phenoxy resin J having a weight average molecular weight of 7,600 was obtained.

・Linear chain phenoxy resin K: Linear phenoxy resin K obtained by the following synthesis procedure J
(Synthesis procedure J)
Synthesis procedure except that a mixture of biphenyl-type epoxy resin and tetramethylbiphenyl-type epoxy resin (mixture of bifunctional epoxy compounds, with mesogenic structure, manufactured by Mitsubishi Chemical Corporation, YL6121HA) was used instead of the above-mentioned tetramethylbiphenyl-type epoxy resin. Synthesis was carried out in the same manner as F to obtain a linear phenoxy resin K having a weight average molecular weight of 8,800.

(thermal conductive filler)
・Thermal conductive filler 1: Granular boron nitride produced by the following procedure (procedure for producing granular boron nitride)
Commercially available boron carbide powder was placed in a carbon crucible and subjected to nitriding treatment at 2000° C. for 10 hours in a nitrogen atmosphere.
Next, commercially available diboron trioxide powder was added to the obtained boron nitride powder and mixed in a blender for 1 hour (boron nitride: diboron trioxide = 7:3 (mass ratio)). The resulting mixture was placed in a carbon crucible and fired at 2000° C. for 10 hours in a nitrogen atmosphere to obtain granular boron nitride.

In Table 1, "resin properties" refers to the cured physical properties of a thermosetting resin composition that does not contain a thermally conductive filler, and "composite properties" refers to the cured physical properties of a thermosetting resin composition that does not contain a thermally conductive filler. It means the cured physical properties of the composition.

<Resin properties>
The obtained thermosetting resin composition containing no thermally conductive filler was evaluated based on the following evaluation items. The evaluation results are shown in Table 1.

(Tg: glass transition temperature)
The obtained thermosetting resin composition containing no thermally conductive filler was heat-treated at 100° C. for 30 minutes to produce a B-stage thermally conductive sheet having a thickness of 400 μm. Next, the thermally conductive sheet was heat-treated at 200° C. for 120 minutes to obtain a cured thermally conductive sheet. Next, the glass transition temperature (Tg) of the obtained cured product was measured by DMA (dynamic viscoelasticity measurement) at a heating rate of 5° C./min and a frequency of 1 Hz.
In Table 1, when the glass transition temperature was less than 180°C, it was judged as △, when it was 180°C or more and less than 200°C, it was judged as ○, and when it was 200°C or more, it was judged as ◎.

(E': storage modulus)
The obtained thermosetting resin composition containing no thermally conductive filler was heat-treated at 100° C. for 30 minutes to produce a B-stage thermally conductive sheet having a thickness of 200 μm. Next, the thermally conductive sheet was heat-treated at 200° C. for 120 minutes to obtain a cured thermally conductive sheet. Next, the storage modulus E' at 50° C. of the obtained cured product was measured by DMA (dynamic viscoelasticity measurement). Here, the storage modulus E' is measured at 50°C from 25°C to 300°C at a frequency of 1 Hz and a heating rate of 5 to 10°C/min by applying a tensile load to the cured thermally conductive sheet. is the value of the storage modulus of

(CTE: coefficient of linear expansion)
Using the obtained thermosetting resin composition containing no thermally conductive filler, curing was performed at 200° C. for 120 minutes to prepare a 4 mm×20 mm test piece. The linear expansion coefficient of the obtained test piece was measured. Using a TMA (Thermal Mechanical Analyzer) test device (TMA/SS6100 manufactured by Seiko Instruments), the temperature increase rate was 5°C/min, the load was 0.05N, the tensile mode was measured, and the measurement temperature range was 30 to 320°C. Two cycles of thermomechanical analysis (TMA) were measured. From the obtained results, the average value of the coefficient of linear expansion (CTE) in the plane direction (XY direction) in the range of 40° C. to 60° C. was calculated. Note that the linear expansion coefficient (ppm/° C.) used the value of the second cycle.

(Td5: 5% weight loss temperature)
The sample was heated from 30°C to 650°C at a heating rate of 10°C/min under a stream of dry nitrogen using a simultaneous differential thermogravimetric measurement device (Seiko Instruments, Model TG/DTA6200). By doing so, the temperature (Td5) at which the sample lost 5% in weight was calculated. As a sample, the resulting thermosetting resin composition containing no thermally conductive filler was heated at 200°C for 120 min to obtain a cured product, and then dried at 100°C for 1 hour before measurement. I used the one that had been applied.
In Table 1, cases where Td5 was 300°C or less were judged as △, cases where Td5 was between more than 300°C and less than 350°C were judged as ○, and cases where Td5 was more than 350°C were judged as ◎.

(Resin thermal conductivity)
・Preparation of resin molding The obtained thermosetting resin composition that does not contain a thermally conductive filler was set in a mold coated with a mold release agent, and compression molding was performed at 220°C for 15 minutes to a size of 10 mm in diameter x 1 mm in thickness. A resin molded product was obtained. Thereafter, curing was performed in an oven at 200° C. for 120 minutes to obtain a resin molded body (sample 1 for thermal conductivity measurement).
- Specific gravity of resin molding Specific gravity measurement was performed based on JIS K 6911 (general test method for thermosetting plastics). The test piece used was a piece cut out from the above composite molded product into a size of 2 cm long x 2 cm wide x 2 mm thick. The unit of specific gravity (SP) is g/ ^cm3 .

- Specific heat of resin molded article The specific heat (Cp) of the obtained resin molded article was measured by the DSC method.

-Measurement of thermal conductivity of resin molded body A test piece was cut out from the obtained resin molded body to a size of 10 mm in diameter and 0.2 mm in thickness for measurement in the thickness direction. Next, the thermal diffusion coefficient (α) in the thickness direction of the plate-shaped test piece was measured by the laser flash method using a Xe flash analyzer TD-1RTV manufactured by ULVAC. The measurements were carried out under atmospheric conditions at 25°C. The results are shown in Table 1.
Thermal conductivity of the resin molded body was calculated from the obtained measured values of thermal diffusion coefficient (α), specific heat (Cp), and specific gravity (SP) based on the following formula.
Thermal conductivity [W/m・K] = α [m ² /s] × Cp [J/kg・K] × Sp [g/cm ³ ]
In Table 1, the thermal conductivity of the resin molded body was defined as "resin thermal conductivity."
In Table 1, when the resin thermal conductivity is less than 0.27 W/m・k, △, when it is 0.27 W/m・k or more and less than 0.29 W/m・k, ○, 0.29 W/m - Cases of k or more were judged as ◎.

<Composite properties>
The thermosetting resin composition varnish containing the obtained thermally conductive filler was evaluated based on the following evaluation items. The evaluation results are shown in Table 1.

(Composite thermal conductivity)
- Preparation of composite molded object A B-stage thermally conductive sheet having a film thickness of 200 μm was prepared by heat-treating the obtained thermosetting resin composition varnish containing the thermally conductive filler at 100° C. for 30 minutes. Next, the thermally conductive sheet was heat-treated at 200° C. for 120 minutes to obtain a cured thermally conductive sheet. A composite molded body (sample 2 for thermal conductivity measurement) measuring 15 cm long x 22 cm wide x 0.2 mm thick was obtained.

- Specific gravity of composite molded product Specific gravity measurement was performed based on JIS K 6911 (general test method for thermosetting plastics). The test piece used was a piece cut out from the above composite molded product into a size of 2 cm long x 2 cm wide x 2 mm thick. The unit of specific gravity (SP) is g/ ^cm3 .

- Specific heat of composite molded article The specific heat (Cp) of the obtained composite molded article was measured by the DSC method.

-Measurement of thermal conductivity of composite molded body A specimen having a diameter of 10 mm and a thickness of 0.2 mm was cut out from the obtained composite molded body for measurement in the thickness direction. Next, the thermal diffusion coefficient (α) in the thickness direction of the plate-shaped test piece was measured by the laser flash method using a Xe flash analyzer TD-1RTV manufactured by ULVAC. The measurements were carried out under atmospheric conditions at 25°C.
For each of the composite molded bodies, the thermal conductivity was calculated based on the following formula from the obtained measured values of thermal diffusion coefficient (α), specific heat (Cp), and specific gravity (SP).
Thermal conductivity [W/m・K] = α [m ² /s] × Cp [J/kg・K] × Sp [g/cm ³ ]
In Table 1, the thermal conductivity of the composite molded body was defined as "composite thermal conductivity."
In Table 1, when the composite thermal conductivity is less than 8 W/m・k, △, when it is 8 W/m・k or more and less than 10 W/m・k, ○, and when it is 10 W/m・k or more, ◎ I decided that.

(Heat conduction stability after heat treatment)
In the same manner as in <Resin Thermal Conductivity> above, the obtained resin molded body was cut out into a piece having a diameter of 10 mm and a thickness of 0.2 mm to prepare a test piece. The test piece was exposed to 260° C. for 5 minutes in an oven (heat treatment). Regarding the test piece after heat treatment, heat was calculated based on the above formula from the measured values of thermal diffusion coefficient (α), specific heat (Cp), and specific gravity (SP) obtained in the same manner as in the above <Resin thermal conductivity>. The conductivity was calculated.
When the resin thermal conductivity after this heat treatment is TC1 and the resin thermal conductivity before heat treatment obtained in <Resin Thermal Conductivity> above is TC0, the test piece (resin molded body) before and after heat treatment The rate of change ΔTC in resin thermal conductivity was calculated from the formula ((TC1-TC0)/TC0)×100.
In the rate of change ΔTC of resin thermal conductivity, when the decrease was 5% or less, it was rated ○, when the decrease was more than 5% to 10% or less, it was rated △, and when the decrease was more than 10%, it was rated ×. The results are shown in Table 1.

100 Metal base substrate 101 Metal substrate 102 Insulating layer 103 Metal layer

Claims (11)

A thermosetting resin composition containing a thermosetting resin, a phenoxy resin, and a thermally conductive filler,
The phenoxy resin contains a compound having a mesogenic structure in the molecule,
When the thermosetting resin composition containing no thermally conductive filler is prepared as a composition sample, and the composition sample is cured to produce a cured sample,
The resin thermal conductivity in the thickness direction of the cured sample is 0.27 W/m·K or more and 3.0 W/m·K or less,
The glass transition temperature of the cured sample is 150°C or more and 400°C or less ,
The thermosetting resin includes one or more selected from the group consisting of epoxy resins and phenol derivatives,
The phenoxy resin contains a branched reaction compound of a polyfunctional phenol compound having three or more hydroxy groups in the molecule and a polyfunctional epoxy compound having two or more epoxy groups in the molecule,
A thermosetting resin composition, wherein at least one of the polyfunctional phenol compound and the polyfunctional epoxy compound has the mesogenic structure in the molecule . A thermosetting resin composition containing a thermosetting resin, a phenoxy resin, and a thermally conductive filler,
The phenoxy resin contains a compound having a mesogenic structure in the molecule,
When the thermosetting resin composition containing no thermally conductive filler is prepared as a composition sample, and the composition sample is cured to produce a cured sample,
The resin thermal conductivity in the thickness direction of the cured sample is 0.27 W/m·K or more and 3.0 W/m·K or less,
The glass transition temperature of the cured sample is 150°C or more and 400°C or less,
The phenoxy resin contains a reaction compound of a polyfunctional phenol compound and a polyfunctional epoxy compound,
The thermosetting resin includes one or more selected from the group consisting of epoxy resins and phenol derivatives,
A thermosetting resin composition, wherein the phenoxy resin contains an addition polymer of a mesogenic structure-containing phenol compound. The thermosetting resin composition according to claim 1 or 2 ,
A thermosetting resin composition, wherein the mesogenic structure has a structure represented by the following general formula (1).
-A ¹ -x-A ² - (1)
(In the above general formula (1), A ¹ and A ² each independently represent an aromatic group, a fused aromatic group, an alicyclic group, or an alicyclic heterocyclic group, and x is a direct bond, or -O-, -C=C-, -C≡C-, -CO-, -CO-O-, -CO-NH-, -CH=N-, -CH=N-N=CH-, - Indicates a divalent bonding group selected from the group consisting of N=N- and -N(O)=N-.) The thermosetting resin composition according to claim 1 ,
A thermosetting resin composition, wherein the polyfunctional phenol compound includes a polyphenol or a polyphenol derivative. The thermosetting resin composition according to any one of claims 1 to 4 ,
A thermosetting resin composition, wherein the phenol derivative includes a phenol derivative having a mesogenic structure in its molecule. The thermosetting resin composition according to any one of claims 1 to 5 ,
The thermally conductive filler is a thermosetting resin composition containing at least one selected from alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, and magnesium oxide. The thermosetting resin composition according to claim 6 ,
The boron nitride is a thermosetting resin composition containing monodispersed particles, aggregated particles, or a mixture thereof of flaky boron nitride. The thermosetting resin composition according to any one of claims 1 to 7 ,
A thermosetting resin composition, wherein the cured sample has a storage modulus of 1.7 GPa or more and 5.0 GPa or less at 25°C. The thermosetting resin composition according to any one of claims 1 to 8 ,
A thermosetting resin composition, wherein the cured sample has a 5% weight loss temperature (Td5) of 330°C or more and 500°C or less. a carrier base material;
A resin sheet comprising a resin layer made of the thermosetting resin composition according to any one of claims 1 to 9 , provided on the carrier base material. a metal substrate;
an insulating layer provided on the metal substrate;
a metal layer provided on the insulating layer,
The insulating layer is a resin layer made of the thermosetting resin composition according to any one of claims 1 to 9 , or a resin layer made of the thermosetting resin composition according to any one of claims 1 to 9 . A metal-based substrate made of cured material.

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